Spider veins are usually found on the legs due to the pressure that leg veins endure throughout daily activities. When it comes to common causes of spider veins in the legs, some are preventable, while others are not. Spider veins on the legs, often seen as red, blue, or purple lines, can sometimes cause pain, itching, or a burning sensation. At USA Vein Clinics, specialists offer advanced, minimally invasive treatments to relieve discomfort and improve appearance.